Coffee products and related processes

ABSTRACT

A coffee milling process comprising the steps of: a) introducing particles of a roasted coffee precursor into a milling chamber; b) introducing particles of soluble coffee into the milling chamber; c) jetting a gas into the milling chamber to mobilise the particles of the roasted coffee precursor and soluble coffee; d) thereby producing a milled and blended coffee product by comminuting the particles of the roasted coffee precursor by self-collision of the particles of the roasted coffee precursor and by collision of the particles of soluble coffee with the particles of the roasted coffee precursor within the milling chamber. Processes and products incorporating milled and blended coffee products are also described.

The present application relates to coffee products and processes forforming coffee products. In particular, it relates to soluble coffeeproducts incorporating a percentage of roasted ground coffee andprocesses for forming such products.

BACKGROUND

Instant soluble coffee products, such as freeze-dried and spray-driedinstant coffee, are well known. An example of a freeze-dried instantcoffee is Kenco® Smooth freeze dried coffee. Such instant soluble coffeeproducts are formed by deriving a liquid coffee concentrate intermediate(commonly known as coffee liquor) from coffee beans by the well knownprocesses of roasting and extraction. Optionally, the coffee concentratemay be aromatized by the addition of coffee aromas stripped from anextracted coffee intermediate, again as well known in the art. Thecoffee concentrate is then subjected to various foaming and drying stepsto produce a dry granular end product that can be reconstituted into acoffee beverage by the addition of hot water.

Instant soluble coffee products are popular with consumers as theyprovide an economical, fast and simple way of preparing a coffeebeverage. However, there has been a desire to produce instant solublecoffee products which are more reminiscent of roasted ground coffeeproducts both in the appearance of the product prior to reconstitutionand when consumed.

It is known to incorporate in a soluble coffee product a percentage ofroasted ground coffee in order to attempt to produce a more appealinginstant soluble coffee product. For example, WO2010/005604 describesvarious soluble coffee products blended from soluble and ground coffeecomponents.

A problem that the present applicant has found with soluble coffeeproducts incorporating a roasted ground coffee component is that it isdifficult to adequately disperse the roasted ground coffee particleswithin the liquid coffee concentrate intermediate. Poor dispersion canlead to clumping of the roasted ground coffee particles on addition tothe liquid coffee intermediate leading to non-hydrated regions ofroasted ground coffee which never fully ‘wet’.

Partly in order to try and overcome the problem of poor dispersion ithas been known to try and reduce the roast and coffee particle size downto colloidal particle sizes of less than about 30 to 40 microns. Forexample, U.S. Pat. No. 4,594,257 describes an agglomerated instantcoffee product comprising spray-dried instant coffee and roasted coffeecolloidal particles having a particle size of 5 to 25 microns.

However, in order to produce colloidal sized particles of roasted groundcoffee it is necessary to utilise special grinding processes since thecoffee oil contained in the roasted ground coffee has a tendency to bereleased when the particles are ground to such a small size. Coffee oilrelease leads to detrimental affects on the grinding process such asclumping of the coffee particles and fouling of the grinding machinesurfaces necessitating regular machine cleaning and consequent downtime.

In order to overcome this problem it is known to cryogenicallypre-freeze the roasted coffee beans prior to them being ground down tocolloidal sizes. For example, in WO2010/005604 the roasted coffee beansare frozen to a temperature of about −5° C. and then pulverised intoparticles with a mean or median particle size of about 350 microns orless. In another example, GB2022394 describes a process of quenchingroasted coffee beans in liquid nitrogen before being ground to aparticle size of less than 45 microns.

The requirement to cryogenically freeze the roasted coffee beans priorto grinding increases the complexity and expense of the manufacturingprocess.

Another suggested solution to permit colloidal grinding of roastedcoffee beans is to add additional oil to the grinding mixture to provideadditional lubrication. Whilst this can in some situations overcome theproblem of fouling of the grinding machine surfaces it results in aground coffee product with a high oil content that is not ideal for useas a coffee intermediate for further processing into an instant solublecoffee beverage since only a relatively small amount can be added toproducts without a detrimental affect on the product composition.

Another suggested solution in EP1631151 is to add an additionalcomponent such as cocoa mass or sugar to absorb any coffee oil releasedby the roasted and ground coffee. However, this process is unsuitablewhere the desire is to use the colloidal roasted ground coffee in a puresoluble coffee beverage.

Another known desire is to attempt to make the visual appearance of theinstant soluble coffee product more like that of roasted ground coffee.Typically, instant soluble coffee products are lighter in colour thanroasted ground coffee. There has therefore been a desire to darken thecolour of instant soluble coffee products, in particular freeze-driedsoluble coffee. Prior art methods for darkening the colour of solublecoffee include the use of steam darkeners as described in EP0700640 andre-wetting of a freeze-dried intermediate as described in EP0090561. Inaddition CO₂ gasification has been used to darken soluble coffeeproducts.

However, prior art techniques for darkening the appearance of a solublecoffee product have certain drawbacks. Re-wetting of the intermediatecoffee product by addition of water or use of steam or the use of gases,such as CO₂, can alter the density and solubility of the end product.

BRIEF SUMMARY OF THE DISCLOSURE

In this specification unless otherwise required by the context, the term“roasted coffee” means a coffee substance that has been produced by theroasting of green coffee beans. The substance may be in the form of aroasted coffee bean or in some other form produced by onward processingsteps such as grinding, decaffeination, pressing, etc. Particularexamples of roasted coffee include roasted coffee beans, roastedexpeller cake, roasted and flaked coffee.

In this specification unless otherwise required by the context, the term“roasted ground coffee” means a roasted coffee substance that has beensubject to a comminution process in order to reduce the particle size ofthe original roasted coffee substance. Again, unless otherwise requiredby the context the comminution process may include one or more ofgrinding, chopping, pounding and crushing.

In this specification, the term “Helos particle size distribution D90”,means the 90th percentile figure by volume of the particle sizedistribution, as obtained from a Helos™ laser light diffraction particlesize analyzer available from Sympatec, Clausthal-Zellerfeld, Germany.That is, the D90 is a value on the distribution such that 90% by volumeof the particles have a characteristic size of this value or less. Thefigure may be obtained for a dry sample (referred to as “dry Helos”) orfor a wet sample (referred to as “wet Helos”), e.g. after mixing of theparticles with water. Likewise for D50 where the value represents the50th percentile figure of the particle size distribution.

Helos is a laser diffraction sensor system for which one evaluationmethod is applied over the whole measuring range from 0.1 μm to 8750 μm.This instrument is designed for particle size analysis of dry and wetsamples, i.e. of powders, suspensions, emulsions or sprays.

For wet Helos measurements, the beverage is made up to 1.5%concentration (3 g solids in 200 ml water) using 100° C. water anddripped into cuvette (with magnetic stirrer coated with PTFE running at1000 RPM) to aim for an optical concentration between 20 and 25%. Whenusing ultrasound, an integrated sonication finger made from Titanium canbe lowered manually into the cuvette.

There are three options to measure particle size on the Helos system:

Settings used for micro Method name Measuring range Application milledcoffee Dry PSD 0.1-3500 μm Direct Lens: R4 (1.8-250 μm measurement forCopt 1.5% ref, with R4) milled product 20 s Dispersion 100% 4 mm 3 barWet PSD 0.1-3500 μm Allows Lens: R3 (0.5-175 μm with dissolution ofCuvette R3) soluble coffee settings product and gives roasted groundparticle size formed in cup by hand stirring Wet PSD 0.1-3500 μm AllowsLens: R3 with (0.5-175 μm with dissolution of Cuvette ultrasound R3)soluble coffee settings and break-up of Ultrasonication roasted groundtime 60 sec clumps giving better indication of individual particle size

Dry Particle Size Distribution is measured using HELOS/KF, R4 Lens,RODOS/M Dispersing System and VIBRI Feeder manufactured by SympatecGmbH.

Wet Particle Size Distribution is measured using HELOS/KF, R3 Lens,CUVETTE Dispersing System manufactured by Sympatec GmbH.

In this specification, the reference to colour in “La units” means theunit reading measured using visible light reflectance of a sample of theroasted ground or soluble coffee using a Dr. Lange® Colour ReflectanceMeter Model LK-100 with an internal 640 nm filter, available from Dr.Lange GmbH, Dusseldorf, Germany. The La scale is based on the Hunter1948 L,a,b, color space, where the L component measures ‘lightness’ withL=0 being black and L=100 being a perfect diffuse reflector. Thereforethe lower the La number the darker the sample measured.

In a first aspect, the present disclosure describes a freeze-driedsoluble coffee product comprising 5 to 30% by dry weight roasted groundcoffee and 70 to 95% by dry weight equivalent soluble coffee, whereinthe roasted ground coffee has a dry Helos particle size distribution D90of less than or equal to 100 microns; the freeze-dried soluble coffeeproduct having a colour of 13 to 30 La units on the Lange scale.

Preferably, the freeze-dried soluble coffee product comprises 10 to 20%by dry weight roasted ground coffee and 80 to 90% by dry weightequivalent soluble coffee. In one example, the freeze-dried solublecoffee product comprises 15% by dry weight roasted ground coffee and 85%by dry weight equivalent soluble coffee.

It will be appreciated that whilst the freeze-dried soluble coffeeproduct has been described as comprising both roasted ground coffee andsoluble coffee this does not preclude the possibility of the productalso comprising additional components.

Surprisingly, it has been found that the incorporation of roasted groundcoffee of small particle size into a freeze-dried soluble coffee productproduces a darker end product that is more visually reminiscent ofroasted ground coffee.

By comparison, prior art freeze-dried soluble coffee products typicallyhave a colour of greater than 25 La units Even use of the prior artprocess of gasification was unable to produce an end product with acolour of less than 21 La units.

Further, prior art roasted ground coffee typically has a colour of 6 to13 La units.

Preferably the roasted ground coffee has a dry Helos particle sizedistribution D90 of less than or equal to 50 microns, more preferablyless than or equal to 30 microns.

Preferably the freeze-dried soluble coffee product has a colour of 16 to25 La units on the Lange scale. More preferably the freeze-dried solublecoffee product has a colour of 17 to 20 La units on the Lange scale.

Preferably the freeze-dried soluble coffee product has a density of 185to 265 g/litre. More preferably the freeze-dried soluble coffee producthas a density of 205 to 235 g/litre. In one example the freeze-driedsoluble coffee product has a density of 225 g/litre.

Advantageously, the darkening of the end product by addition of roastedground coffee particles allows an end product to be produced thatachieves consumer-expected density and solubility levels.

Preferably the freeze-dried soluble coffee product has a particle sizerange of 0.3 to 3.5 mm. More preferably the freeze-dried soluble coffeeproduct has a particle size range of 0.3 to 2.5 mm. In one example thefreeze-dried soluble coffee product has a particle size range of 0.3 to1.5 mm.

The freeze-dried product is enabled to be ground and sieved to aparticle size that is reminiscent of a roasted ground coffee product.

The roasted ground coffee may be obtained by known processes such ascryogenic milling of roasted coffee beans as well known in the art anddescribed, by way of example, in GB2022394 noted above. However,preferably the roasted ground coffee is obtained by the novelcomminution process of a fourth aspect of the present disclosure as willbe described further below.

Preferably, the freeze-dried soluble coffee product is produced by thenovel process of a second aspect of the present disclosure which will bedescribed further below.

In a second aspect, the present disclosure describes a process offorming a freeze-dried soluble coffee product, comprising the steps of:

-   i) forming a concentrated coffee extract;-   ii) foaming and pre-freezing the concentrated coffee extract to form    a foamed and pre-frozen coffee intermediate;-   iii) freezing the foamed and pre-frozen coffee intermediate to form    a frozen coffee intermediate;-   iv) grinding and sieving the frozen coffee intermediate to form a    ground coffee intermediate;-   v) drying the ground coffee intermediate to form the freeze-dried    soluble coffee product;

wherein prior to step ii) and/or step iii) a milled and blended coffeeintermediate is incorporated;

wherein the milled and blended coffee intermediate comprises 10 to 80%by dry weight roasted ground coffee and 20 to 90% by dry weight solublecoffee.

In a third aspect, the present disclosure describes a process of forminga spray-dried soluble coffee product, comprising the steps of:

-   i) forming a concentrated coffee extract;-   ii) foaming the concentrated coffee extract to form a foamed coffee    intermediate;-   iii) optionally filtering and homogenizing the foamed coffee    intermediate to form a filtered and homogenized coffee intermediate;-   iv) spray drying the foamed coffee intermediate or the filtered and    homogenized coffee intermediate to form the spray-dried soluble    coffee product;

wherein prior to step ii) and/or step iv) a milled and blended coffeeintermediate is incorporated;

wherein the milled and blended coffee intermediate comprises 10 to 80%by dry weight roasted ground coffee and 20 to 90% by dry weight solublecoffee.

Surprisingly, it has been found that incorporating a milled and blendedcoffee intermediate (formed from roasted ground coffee particles andsoluble coffee particles) as part of the soluble coffee forming processresults in very good dispersion of the roasted ground particlesthroughout the concentrated coffee extract

Preferably, the milled and blended coffee intermediate of the second orthird aspects comprises 10 to 70% by dry weight roasted ground coffeeand 30 to 90% by dry weight soluble coffee. More preferably, the milledand blended coffee intermediate of the second or third aspects comprises15 to 50% by dry weight roasted ground coffee and 50 to 85% by dryweight soluble coffee. In one example the milled and blended coffeeintermediate of the second or third aspects comprises 50% by dry weightroasted ground coffee and 50% by dry weight soluble coffee.

It will be appreciated that whilst the milled and blended coffeeintermediate of the second or third aspects has been described ascomprising both roasted ground coffee and soluble coffee this does notpreclude the possibility of the intermediate also comprising additionalcomponents.

Preferably, the milled and blended coffee intermediate of the second orthird aspects has a dry Helos particle size distribution D90 of lessthan or equal to 40 microns. More preferably the milled and blendedcoffee intermediate of the second or third aspects has a dry Helosparticle size distribution D90 of less than or equal to 30 microns.

Preferably, in the process of the second or third aspects thefreeze-dried or spray-dried coffee product comprises 5 to 30% by dryweight roasted ground coffee and 70 to 95% by dry weight equivalentsoluble coffee. More preferably the freeze-dried or spray-dried coffeeproduct comprises 10 to 20% by dry weight roasted ground coffee and 80to 90% by dry weight equivalent soluble coffee. In one example thefreeze-dried or spray-dried coffee product comprises 15% by dry weightroasted ground coffee and 85% by dry weight equivalent soluble coffee.

It will be appreciated that whilst the freeze-dried or spray-driedcoffee product has been described as comprising both roasted groundcoffee and soluble coffee this does not preclude the possibility of theproduct also comprising additional components.

The soluble coffee of the milled and blended coffee intermediate maycomprise spray-dried instant coffee, freeze-dried instant coffee, or amixture thereof.

The ground coffee intermediate of the process of forming a freeze-driedsoluble coffee product described above prior to drying may have a totalcoffee solids concentration of greater than or equal to 52% and lessthan or equal to 63%.

The coffee intermediate of the process of forming a spray-dried solublecoffee product described above prior to drying may have a total coffeesolids concentration of greater than or equal to 52% and less than orequal to 63%.

In either case the total coffee solids concentration may preferably be56% to 60%.

The second and third aspects of the present disclosure extend to asoluble coffee product produced by the above described processes.

In addition, the second and third aspects of the present disclosureextend to a coffee beverage formed using the soluble coffee productdescribed above.

In a fourth aspect, the present disclosure describes a coffee millingprocess comprising the steps of:

-   a) introducing particles of a roasted coffee precursor into a    milling chamber;-   b) introducing particles of soluble coffee into the milling chamber;-   c) jetting a gas into the milling chamber to mobilise the particles    of the roasted coffee precursor and soluble coffee;-   d) thereby producing a milled and blended coffee product by    comminuting the particles of the roasted coffee precursor by    self-collision of the particles of the roasted coffee precursor and    by collision of the particles of soluble coffee with the particles    of the roasted coffee precursor within the milling chamber.

Advantageously, comminuting the roasted coffee precursor in this mannerhas been found to provide an excellent means for reducing the particlesize of the roasted coffee without the deleterious effects previouslyencountered by release of coffee oil from the roasted coffee precursor.Without wishing to be bound by theory, it is understood that theincorporation of the particles of soluble coffee into the millingchamber results in the soluble coffee absorbing some, and preferablymost or all of the coffee oil released during comminution.

Advantageously, the particles of soluble coffee are actively used as acomminuting agent within the milling chamber by impacting the particlesof the roasted coffee precursor with the particles of soluble coffee.There will of course be some comminution of the roasted coffee precursorby self-collision—in other words, particles of roasted coffee precursorimpacting other particles of roasted coffee precursor. However, it hasbeen found that the additional comminution caused by impacting theroasted coffee precursor with particles of soluble coffee produces anenhanced milling action. This is particularly surprising consideringthat the particles of soluble coffee are not particularly hard.

If preferred, the mobilised roasted coffee particles can be directed toimpact additional surfaces, such as impact plates, of the millingchamber to provide additional comminution effects. However, the use ofsuch impacts is not essential to the process.

The particles of the roasted coffee precursor and the soluble coffee maybe mixed together before introduction into the milling chamber. Forexample, the ingredients may be batch mixed in the dry form andintroduced into the milling chamber via a common hopper feed.

Alternatively the particles of the roasted coffee precursor and thesoluble coffee may be introduced separately into the milling chamber.For example separate hoppers for the roasted coffee precursor and thesoluble coffee precursor may be provided.

Another possibility is the use of a single feed line which may be usedto jet one precursor into the milling chamber which acts to entrain theother precursor into the flow.

Preferably the particles of the roasted coffee precursor in step a) areat a temperature of between 5 and 30 degrees Celsius.

Preferably the milling chamber is not subject to cryogenic coolingduring steps b), c) and d).

A particular advantage of the aspects of the present disclosure is thatcryogenic cooling of the roasted coffee precursor to prevent coffee oilrelease is not required, even where the milling is down to colloidalparticle sizes. The coffee precursor may optionally be subject to somepre-chilling before milling, for example by being refrigerated to atemperature as low as 5 degrees Celsius. However, the roasted coffeeprecursor may also be used at ambient temperature (typically 20 to 25degrees Celsius).

In addition, it is not essential that the physical components of themilling apparatus (chamber walls, feed lines, etc.) are cooled. However,it may be desirable to chill the jetting gas in order to help removemoisture during the milling process. The chilled gas will result in somecooling of the milling apparatus. However, this is significantly lessthan typically results during cryogenic cooling. The gas may be at atemperature between −20 degrees Celsius and ambient temperature. In oneexample gas at a temperature of −16 degrees Celsius was used.

The absence of active cooling (or the use of minimal cooling asdescribed above) considerably reduces the complexity of the machineryrequired for the milling process, speeds up the process time and reducesthe costs associated with the milling stage of the process.

Preferably the milled and blended coffee product produced in step d)comprises 10 to 80% by dry weight roasted ground coffee and 20 to 90% bydry weight soluble coffee. More preferably the milled and blended coffeeproduct produced in step d) comprises 10 to 70% by dry weight roastedground coffee and 30 to 90% by dry weight soluble coffee. Even morepreferably the milled and blended coffee product produced in step d)comprises 15 to 50% by dry weight roasted ground coffee and 50 to 85% bydry weight soluble coffee. In one example the milled and blended coffeeproduct produced in step d) comprises 50% by dry weight roasted groundcoffee and 50% by dry weight soluble coffee. Milling to produce aproduct containing above 70% by dry weight roasted ground coffee may bemade possible where the feed gas is chilled down to a temperature ofaround −20 degrees Celsius as discussed above. Otherwise limiting thepercentage of roasted ground coffee in the product to a maximum of 70%is preferred.

It will be appreciated that whilst the milled and blended coffee producthas been described as comprising both roasted ground coffee and solublecoffee this does not preclude the possibility of the product alsocomprising additional components.

Preferably in step d) the comminution results in the milled and blendedcoffee product having a dry Helos particle size distribution D90 of lessthan or equal to 40 microns. More preferably in step d) the comminutionresults in the milled and blended coffee product having a dry Helosparticle size distribution D90 of less than or equal to 30 microns.

The particles of roasted coffee precursor may be whole roasted coffeebeans or coarsely-ground roasted coffee beans. The process findsapplication with whole roasted coffee beans which provides a simplifiedprocess route. However, if desired, an initial coarse grind of theroasted coffee beans can be carried out before the roasted coffee isinserted into the milling chamber.

The particles of soluble coffee may be particles of spray-dried instantcoffee, particles of freeze-dried instant coffee, or a mixture thereof.

There may be advantages in using a soluble coffee type that matches thetype of end product that the milled and blended coffee product is to beutilised in. For example, where ultimately the milled and blended coffeeproduct is to be incorporated in a freeze-dried coffee product then thesoluble coffee product used as a comminuting agent in the millingchamber may be chosen also to be freeze-dried soluble coffee. However,the types of soluble coffee used in the process may be mixed and alteredas desired.

Preferably the gas jetted into the milling chamber in step b) isnitrogen, air, or a mixture thereof.

The milling chamber may form part of a jet mill. Examples of such millsinclude fluid bed opposed jet mills, Jet-O-Mizer™ mills, vortex mill,spiral mills, etc.

The fourth aspect of the present disclosure extends to a milled andblended coffee product produced by the process described above.

The milled and blended coffee product may be used as a milled andblended coffee intermediate in the processes of the second and thirdaspects of the present disclosure described above. Alternatively, themilled and blended coffee product may be used in the onward productionof other coffee-based products. Further, the milled and blended coffeeproduct may be packaged and sold as an end product in its own right.

The present disclosure extends to a container containing the milled andblended coffee product described above or the soluble coffee productdescribed above or the freeze-dried soluble coffee product describedabove.

The container may be a bottle, a jar, a tin, a refill pack, a sachet, astick pack, a filter bag or a container suitable for use in a beveragepreparation machine such as a flexible pad formed at least partly fromfiltering material, or a rigid, semi-rigid or flexible cartridge formedfrom substantially air- and water-impermeable materials.

The container may further contain one or more additional beveragecomponents such as natural or artificial sweeteners, dairy or non-dairybased creamers, lactose, vegetable fat, whey proteins, emulsifiers,stabilisers, modified starches, carriers, fillers, flavours, colours,nutrients, preservatives, flow agents or foaming agents.

The present disclosure extends to a beverage preparation machine incombination with at least one container suitable for use in saidbeverage preparation machine such as a flexible pad formed at leastpartly from filtering material, or a rigid, semi-rigid or flexiblecartridge formed from substantially air- and water-impermeablematerials, said at least one container containing the milled and blendedcoffee product described above or the soluble coffee product describedabove or the freeze-dried soluble coffee product described above.

The present disclosure extends to method of making a beverage comprisingthe step of mixing the milled and blended coffee product described aboveor the soluble coffee product described above or the freeze-driedsoluble coffee product described above with an aqueous liquid,preferably hot water.

The mixing may be performed by a beverage preparation machine.Alternatively, the mixing may be by hand in a receptacle.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will now be described, by way ofexample only, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic illustration of the workings of a jet mill;

FIG. 2 is a graph of particle size in microns against Helos particlesize distribution D90;

FIG. 3 is a flow diagram illustrating prior art processes for formingfreeze-dried and spray-dried soluble coffee;

FIG. 4 a is a flow diagram illustrating a process for forming afreeze-dried soluble coffee product according to the present disclosure;

FIG. 4 b is a flow diagram illustrating a modification of the process ofFIG. 4 a;

FIG. 5 a is a flow diagram illustrating another process for forming afreeze-dried soluble coffee product according to the present disclosure;

FIG. 5 b is a flow diagram illustrating a modification of the process ofFIG. 5 a;

FIG. 6 is a flow diagram illustrating a process for forming aspray-dried soluble coffee product according to the present disclosure;

FIG. 7 is a flow diagram illustrating another process for forming aspray-dried soluble coffee product according to the present disclosure;

FIG. 8 is a graph of colour reduction in La units for variousfreeze-dried soluble coffee products;

FIG. 9 shows a first example of container;

FIG. 10 shows a second example of container;

FIG. 11 shows an example of a beverage preparation machine;

FIGS. 12 to 15 show scanning electron microscope photographs of varioussample products.

DETAILED DESCRIPTION

In one aspect of the present disclosure a milled and blended coffeeproduct may be produced by comminuting a roasted coffee precursor in amilling apparatus such as a jet mill. A suitable jet mill is theJet-O-Mizer™ mill available from Fluid Energy Processing and EquipmentCompany, Telford, Pa., USA. Another suitable mill is the Hosokawa AlpineFluid Bed Opposed Jet Mill—AFG, available from Hosakawa Micron Ltd,Runcorn, Cheshire, United Kingdom. Other suitable milling apparatusinclude mills referred to as spiral mills and vortex mills.

A schematic illustration of the working principles of a jet mill isshown in FIG. 1. The mill 1 comprises a milling chamber 2 having a feedinlet 3, a series of gas inlets 4, a size classification wheel 8 and aproduct outlet 5.

The milling chamber 2 of FIG. 1 takes the form of a generallycylindrical body having the gas inlets 4 at a lower end and spacedaround the periphery and the product outlet 5 located near an upper end.

The feed inlet 3 communicates with the milling chamber 2 to allowingredient precursor(s), in the form of whole or coarsely-ground roastedcoffee beans and soluble coffee particles, to be fed into the millingchamber 2 tangentially at a location at or near the chamber periphery.

The size classification wheel 8 is located near the upper end of themilling chamber 2 and is adapted to received comminuted particles fromthe chamber 2 and pass those under a desired particle size to theproduct outlet 5.

The roasted coffee precursor and the soluble coffee precursor are drybatch mixed at the required ratio and then deposited in a hopper whichcommunicates with the feed inlet 3 as shown schematically in FIG. 1 byarrow A. A feed gas supply may be provided to entrain the precursorsfrom the hopper and convey them to the chamber 2.

Compressed gas is supplied in use to the plurality of gas inlets 4. Thegas inlets 4 are orientated at an angle to the radial direction of thechamber 2—preferably tangentially to the chamber 2—such that flow of gasthrough the gas inlets 4 sets up a swirling, spiralling gas flow withinthe chamber 2.

In use, to comminute the roasted coffee precursor, the precursors arefed into the chamber 2 and mobilised in the chamber 2 by the high speedflow of gas entering the chamber 2 through the gas inlets 4 (and alsothe feed gas (where used) entering with the precursors through the feedinlet 3).

Comminution occurs due to the high velocity collisions between theparticles of roasted coffee precursor and the soluble coffee resultingin pulverisation of the roasted coffee precursor. As the particle sizereduces the smaller particle sizes move up the chamber 2 into the sizeclassification wheel 8. The size classification wheel 8 acts to classifythe particles it receives and pass onward to the product outlet 5 thoseparticles less than a desired particle size. The particles exit the millas shown schematically in FIG. 1 by arrow B. The larger particles areretained in the chamber and are subject to further comminution. Thus,the jet mill also helps to classify the particle size output through theproduct outlet 5.

Depending on the type of jet mill, the orientation and configuration ofthe milling chamber 2, gas inlets 4, and product outlet 5 can bealtered.

The gas supplied to the gas inlets 4 and the feed gas for conveying theroasted coffee precursor into the chamber 2 may be air, but ispreferably an inert gas, such as nitrogen. The feed gas may bedehumidified and/or chilled in order to help remove moisture from thechamber 2 generated during milling. Dehumidification may be, forexample, by use of a desiccant- or compressor-based dehumidifier. Inaddition, or alternatively, the gas supplied to the gas inlets 4 may bechilled.

The roasted coffee precursor may be whole roasted coffee beans oralternatively may be coffee beans that have been coarsely ground using aconventional milling process to have a particle size of greater than 100microns.

The soluble coffee may be a spray-dried or freeze-dried instant coffeeproduct. The particle size of the soluble coffee product before jetmilling is typically between 100 and 350 microns for spray-dried solublecoffee and 0.1 to 3.5 mm for freeze-dried soluble coffee.

It is not necessary for the mill 1 to be subjected to cryogenic coolingprior or during the milling process. Rather, the mill 1 is preferablyoperated at substantially the ambient temperatures existing at thelocation where the mill 1 is situated.

As noted above, the feed gas and/or gas supplied to the gas inlets mayoptionally be chilled which may result in a modicum of cooling of theapparatus components. For example it has been found that the throughputof the jet mill may be beneficially increased by using cool gas suppliedto the gas inlets 4, for example to a temperature of −16 degreesCelsius, in particular where the ratio of dry weight of roasted groundcoffee to dry weight soluble coffee in the milled and blended coffeeproduct is greater than 50%. In particular this may allow the percentageby dry weight of the roasted ground coffee in the mix to be up to 80%.The following results were achieved using a Roto-Jet 15 mill availablefrom Fluid Energy Processing and Equipment Company, Telford, Pa., USA.The mill was fed with 100% Arabica beans roasted to 8 La. The pressureto the gas inlets 4 was 7 bar and the supplied gas was desiccated airwhich was cooled to +5 degrees Celsius for the first sample and −16degrees Celsius for the second sample. For both samples the classifierof the jet mill was controlled to produce a particle size distributionD90 of 30 microns.

Ratio of roasted Equivalent ground roast & coffee to Total ground coffeesoluble Grinding Throughput throughput coffee Mill Air Temp (kg/hr)kg/hr 70/30 Fluid bed Jet-  +5° C. 20.9 14.6 Mill 70/30 Fluid bed Jet-−16° C. 68.2 47.7 Mill

As can be seen, use of an air temperature of −16 degrees Celsius resultsin a significant increase in the throughput of the jet mill while stillmaintaining the required particle size distribution.

However, it is to be noted that this is still a relatively hightemperature compared to prior art cryogenic cooling processes and it isto be noted that the roasted coffee precursor and soluble coffee are notsubject to cryogenic cooling before entering the jet mill.

The roasted coffee precursor is not subjected to cryogenic cooling orany cryogenic pre-treatment prior to milling. Typically, the temperatureof the roasted coffee precursor when filled into the hopper 6 will be inthe range 5 to 30° C. The roasted coffee precursor may be at the ambientroom temperature of the milling apparatus.

The milled and blended coffee product obtained from product outlet 5comprises 20 to 90% by dry weight soluble coffee and 10 to 80% by dryweight roasted ground coffee. Preferably the milled and blended coffeeproduct obtained from product outlet 5 comprises 30 to 90% by dry weightsoluble coffee and 10 to 70% by dry weight roasted ground coffee. Morepreferably the milled and blended coffee product comprises 50 to 85% bydry weight soluble coffee and 15 to 50% by dry weight roasted groundcoffee. In one example the milled and blended coffee product comprises50% by dry weight soluble coffee and 50% by dry weight roasted groundcoffee.

After milling, the milled and blended coffee product has a particle sizedistribution with a dry Helos particle size distribution D90 of lessthan or equal to 40 microns, more preferably less than or equal to 30microns.

EXAMPLES

FIG. 2 shows results for the dry Helos particle size distribution D90(and in addition wet Helos figures) for milled and blended coffeeproducts produced according to the present disclosure as a function ofthe dry weight percentage of roasted ground coffee present. As can beseen, from 10 to 70% of roasted ground coffee the dry Helos particlesize distribution D90 is less than or equal to 40 microns. Above 70%roasted ground coffee the dry Helos particle size distribution D90increases deleteriously. (As noted above, this may be ameliorated bychilling the feed gas to the jet mill). At or below 50% roasted groundcoffee a dry Helos particle size distribution D90 of 30 microns or lessis achievable.

In a separate example, a blend of Brazilian and Columbian Arabica beanswas roasted to a colour of 11.5 La and pre-ground to a D50 of 500microns. The resulting roasted coffee precursor was dry batch mixed withArabica spray-dried coffee at a ratio of 50% roasted coffee precursor to50% spray-dried coffee precursor. The resultant blend was then milled ina Hosokawa Alpine Fluid Bed Opposed Jet Mill—AFG at a variety of feedrates and classifiers speeds. The following results were obtained:

Classifier Feed Rate Speed Run time Dry Helos Dry Helos (kg/hour) (RPM)(mins.) D50 D90 120 2350 30 10.5 27.5 50 2000 38 11.4 28.7 50 2000 6011.0 27.2

Advantageously, as can be seen for each example a dry Helos particlesize distribution D90 of less than 30 microns was obtainable at a rangeof feed rates and classifier speeds.

Another aspect of the present disclosure relates to processes forproducing novel soluble instant coffee products incorporating a milledand blended coffee product containing a percentage of roasted groundcoffee.

Prior art processes for forming spray-dried and freeze-dried solublecoffee both start with the steps of producing a coffee concentrateintermediate from coffee beans by the processes of roasting andextraction. FIG. 3 illustrates the stages involved. Green coffee beansare roasted and then ground before being added to water to extract thecoffee bean constituents. Optionally, coffee aroma may be stripped atthis point to produce a liquid aroma product. The extraction liquid isthen concentrated, for example in percolation columns to produce aconcentrated extract, commonly known as coffee liquor. Optionally, atthis point the previously produced aroma product may be incorporated toproduce an aromatised coffee concentrate intermediate. Such processesare well known.

The remainder of the procedure depends on whether the soluble product isto be spray-dried or freeze-dried. For spray-dried soluble coffee theremaining process steps include foaming, filtering and homogenising andspray drying to produce the spray-dried product. For freeze-driedsoluble coffee the remaining process steps include foaming andpre-freezing, freezing, grinding & sieving and vacuum drying.

According to the present disclosure these known processes are adapted bythe incorporation of a milled and blended coffee intermediate containinga percentage of roasted ground coffee. In each of the processesdescribed below, the milled and blended coffee intermediate itself maycontain 10 to 80% by dry weight roasted ground coffee and 20 to 90% bydry weight soluble coffee. Preferably, the milled and blended coffeeintermediate contains 10 to 70% by dry weight roasted ground coffee and30 to 90% by dry weight soluble coffee. More preferably, the milled andblended coffee intermediate contains 15 to 50% by dry weight roastedground coffee and 50 to 85% by dry weight soluble coffee. In one examplethe milled and blended coffee intermediate comprises 50% by dry weightsoluble coffee and 50% by dry weight roasted ground coffee.

The soluble coffee component of the milled and blended coffeeintermediate in any of the processes below may be derived fromspray-dried instant coffee, freeze-dried instant coffee, or a mixturethereof.

The milled and blended coffee intermediate preferably has a dry Helosparticle size distribution D90 of less than or equal to 40 microns, morepreferably less than or equal to 30 microns.

In each of the processes described below the end coffee product maycomprise 5 to 30% by dry weight roasted ground coffee and 70 to 95% bydry weight equivalent of soluble coffee. (For example, a soluble coffeeend product containing 15% by dry weight roasted ground coffee and 85%by dry weight equivalent soluble coffee can be obtained by mixing theliquid coffee concentrate with a dry milled and blended coffeeintermediate having 50% by dry weight roasted ground coffee and 50% bydry weight soluble coffee in a ratio of 70:30 coffee concentrateintermediate to milled and blended coffee intermediate.

In a preferred option, the milled and blended coffee intermediate isproduced using the novel process of the present disclosure describedabove with reference to FIG. 1. However, milled and blended coffeeintermediates having the requisite percentages of roasted ground coffeeand soluble coffee may be used, even where produced by alternativemeans.

FIG. 4 a shows a first freeze-dried process for forming a freeze-driedsoluble coffee product 25. A coffee concentrate intermediate 20(aromatised or non-aromatised) is mixed with a milled and blended coffeeintermediate 30 using a high shear mixer 50 prior to the foaming andpre-freezing step 21. Suitable mixers include high shear batch mixersand high shear in-line mixers available from Silverson Machines Ltd,Chesham, United Kingdom. The mixture is then foamed and pre-frozen atstep 21 and then fed to a belt freezer 22 for a further freezing step.The frozen intermediate is then ground and sieved at step 23 to producea particle size range of 0.3 to 3.5 mm, preferably 0.3 to 2.5 mm, morepreferably 0.3 to 1.5 mm. The intermediate is then vacuum dried at step24 to produce the freeze-dried soluble coffee product 25. The productmay then be packed in a container.

A modification to the process of FIG. 4 a is shown in FIG. 4 b. Theprocess is as described above with reference to FIG. 4 a up to step 22.At step 23, however, the frozen intermediate is ground and sieved toproduce a larger particle size range of 1.0 to 3.5 mm. The intermediateis then vacuum dried at step 24 to produce an intermediate freeze-driedsoluble coffee product 25 a. At step 26 the intermediate freeze-driedsoluble coffee product 25 a is subject to a secondary grinding to reducethe particle size range to 0.3 to 1.5 mm to produce the freeze-driedsoluble coffee product 25. The product may then be packed in acontainer.

FIG. 5 a shows a second freeze-dried process for forming a freeze-driedsoluble coffee product 25. The process is the same as the first processdescribed above with reference to FIG. 4 a with the exception that themilled and blended coffee product 30 is incorporated after the foamingand pre-freezing step 21. Again, a high shear mixer 50 of the typedescribed above may be used and in other respects the process is thesame as the first process.

A modification to the process of FIG. 5 a is shown in FIG. 5 b. Theprocess is as described above with reference to FIG. 5 a up to step 22.At step 23, however, the frozen intermediate is ground and sieved toproduce a larger particle size range of 1.0 to 3.5 mm. The intermediateis then vacuum dried at step 24 to produce an intermediate freeze-driedsoluble coffee product 25 a. At step 26 the intermediate freeze-driedsoluble coffee product 25 a is subject to a secondary grinding to reducethe particle size range to 0.3 to 1.5 mm to produce the freeze-driedsoluble coffee product 25. The product may then be packed in acontainer.

An advantage of the modified processes of FIGS. 4 b and 5 b is that theparticle size during vacuum drying is larger than in the processes ofFIGS. 4 a and 5 a which has been found to lead to less product lossesduring drying. It has been found that with the processes of FIGS. 4 aand 5 a potential product losses occur when vacuum drying very smallparticle sizes due to the particles being carried off along with theevaporating water content of the intermediate.

A further advantage of each of the freeze-drying processes of thepresent disclosure described above is that it has been surprisinglyfound that a better freeze-drying performance is achieved and a higherconcentration of soluble solids can be incorporated in the product priorto freeze drying where finely milled roasted ground coffee is included.

The term ‘freeze-drying performance’ refers to the avoidance of driedproduct quality problems, specifically melt-back and sticky lumps.‘Melt-back’ refers to the failure to remove water from each granulestructure by sublimation during freeze drying, and ‘sticky lumps’ arisefrom the failure to remove water vapour that has sublimated fromindividual granules from the overall coffee bed tray.

A typical freeze drying process involves freezing of foamed coffeeextract on a cold room belt. When frozen, the coffee slab is granulatedand sieved to a particular granule size before drying in a freeze-dryer.

The capacity of a freeze dryer is limited by its de-watering ability.The amount of water in the frozen coffee particles fed to thefreeze-drier is dependent on the concentration of total coffee solids ofthe liquid coffee extract when it is frozen. The higher the coffeesolids concentration the lower the water content and thus thefreeze-drier requires less utilisation of its capacity to remove thatwater.

Therefore for a given de-watering ability of a freeze-drier one mightattempt to increase product throughput by increasing the solidsconcentration fed to the dryer. However, increasing the concentrationhas previously been found to have a detrimental effect on productquality such as melt back of product and production of sticky lumps ofagglomerated granules. Because of this limitation, it has beenpreviously accepted that the feed extract should contain no more thanabout 50% total coffee solids.

However, according to the processes and products of the presentdisclosure it has been found that total coffee solids concentrations ofup to 63% can be fed to a freeze-drier while avoiding melt-back andsticky lumps. For example, superior extracts of 56% and 60%concentration may be formed with 15% (by dry weight) of finely milledroasted ground coffee, with a particle size D50 of 30 to 40 microns anda D99 of below 60 microns, and 85% (by dry weight) of pure solublecoffee solids.

EXAMPLES

To illustrate the improved drying performance and product qualities, thefollowing freeze-dried samples were prepared. In each case, the baseextract was prepared by re-dissolving freeze-dried granules and addingwater to make the required concentration of coffee solids. Drying wascarried out under the same conditions for all samples: the dryer was aRayl model available from GEA Niro, of Soeborg, Denmark; samples weredried in a standard tray with the heating profile, initial productweight, particle size of feed material to dryer being identical.

Sample 1-1 (Comparative)

The final extract had a coffee solids concentration of 56% (exclusivelypure soluble coffee solids) and was foamed by air, frozen, grinded,sieved between 0.7 mm-3.35 mm sizes, and finally vacuum dried. Icecoffee granules were frozen at −40 degrees C. and vacuum dried for 3.0hrs or 3.4 hrs.

Frozen and grinded coffee granules Dry product after before dryingfreeze-drying Water (%) 44 0 Soluble coffee 56 100 solids (%) Insolublecoffee 0 0 solids (%)

Sample 2-1

The final extract had a coffee solids concentration of 56% (made-up bysoluble coffee solids from the base extract and coffee solids from thefinely milled roasted ground coffee added before foaming with the endproduct comprising 15% by dry weight roasted ground coffee and 85% bydry weight equivalent soluble coffee) and was foamed by air, frozen,grinded, sieved between 0.7 mm-3.35 mm sizes and finally dried. Icecoffee granules were frozen at −40 degrees C. and vacuum dried for 3.0hrs or 3.4 hrs.

Frozen and grinded coffee granules Dry product after before dryingfreeze-drying Water (%) 44 0 Soluble coffee 48 85 solids (%) Insolublecoffee 8 15 solids (%)

The presence of sticky lumps was quantified by sieving using a 3.35 mmsize sieve, with the following results:

Sample 1-1 (Comparative) Sample 2-1 Feed to Dryer 56% 56% 56% 56%concentration (%) Drying time (Hrs) 3.4 3.0 3.4 3.0 Stickied Free flowof clumps clumps yes yes granules product from tray Quantity (%) 60.965.9 0.4 0.1 Physical Density 21.5 22.3 21.6 21.9 quality (g/100 ml)

As can be seen the inclusion of finely milled roasted ground coffeesubstantially eliminates the presence of sticky lumps.

As well as comparison by sieving, direct visual comparison was made byscanning electron microscope (SEM) photographs. FIG. 12 shows SEMphotographs of the dried coffee products of Sample 1-1. while FIG. 13shows SEM photographs of the dried coffee products of Sample 2-1.

As can be seen from the photos, Samples 2-1 containing finely milledroasted ground coffee show fewer collapsed areas in their structurecompared to pure soluble solids Samples 1-1.

Samples 1-2 (Comparative)

The final extract had a coffee solids concentration of 60%, (exclusivelypure soluble coffee solids) and was foamed by air, frozen, grinded,sieved between 0.7 mm-3.35 mm sizes and finally vacuum dried. Ice coffeegranules were frozen at −40 C and vacuum dried for 3.0 hrs.

Frozen and grinded coffee granules Dry product after before dryingfreeze-drying Water (%) 40 0 Soluble coffee 60 100 solids (%) Insolublecoffee 0 0 solids (%)

Samples 2-2

The final extract had a coffee solids concentration of 60% (made-up bysoluble coffee solids from the base extract and coffee solids from thefinely milled roasted ground coffee added before foaming with the endproduct comprising 15% by dry weight roasted ground coffee and 85% byweight equivalent soluble coffee) and was foamed by air, frozen,grinded, sieved between 0.7 mm-3.35 mm size and finally dried. Icecoffee granules were frozen at −40 C and vacuum dried for 3.0 hrs.

Frozen and grinded coffee granules Dry product after before dryingfreeze-drying Water (%) 40 0 Soluble coffee 51 85 solids (%) Insolublecoffee 9 15 solids (%)

Again, the presence of sticky lumps was quantified by sieving using a3.35 mm size sieve, with the following results:

Sample 1-2 (Comparative) Sample 2-2 Feed to Dryer 60% 60% concentration(%) Drying time (Hrs) 3.0 3.0 Stickied Free flow of clumps yes granulesproduct from tray Quantity (%) 66 0 Physical Density 22.0 22.7 quality(g/100 ml)

Direct visual comparison was made by scanning electron microscope (SEM)photographs. FIG. 14 shows an SEM photograph of the dried coffee productof Sample 1-2. while FIG. 15 shows an SEM photograph of the dried coffeeproduct of Sample 2-2.

As can be seen from the photos, Sample 2-2 containing finely milledroasted ground coffee shows fewer collapsed areas in structure comparedto Sample 1-2.

As another, separate benefit it has been found that the grinding offrozen coffee extract, which contains finely milled roasted groundcoffee produces improved grinding performance in that fewer fines aregenerated compared to frozen coffee extracts formed from pure solublecoffee:

Frozen coffee chips Product (0.7-3.335 mm) Fines (below 0.7 mm) 56%concentration 80% 20% with finely milled roasted ground coffee 56%concentration 75% 25% without finely milled roasted ground coffee 60%concentration 79% 21% with finely milled roasted ground coffee 60%concentration 75% 25% without finely milled roasted ground coffee

For the grinding, the same machine, process and parameters were used:Grinder screen 8 mm, sieve screen 0.7-3.35 mm

FIG. 6 shows a first spray-dried process for forming a spray-driedsoluble coffee product 44. A coffee concentrate intermediate 20(aromatised or non-aromatised) is mixed with a milled and blended coffeeintermediate 30 using a high shear mixer 50 prior to the foaming step41. A high shear mixer 50 of the type described above may be used. Themixture is then foamed at step 41 and then filtered and optionallyhomogenised at step 42. The intermediate is then spray dried at step 43to produce the spray-dried soluble coffee product 44. The product maythen be packed in a container.

FIG. 7 shows a second spray-dried process for forming a spray-driedsoluble coffee product 44. The process is the same as the firstspray-dried process described above with the exception that the milledand blended coffee product 30 is incorporated into a dry mix. Inparticular, the spray-drying apparatus (as known in the art) comprises afines collector for recycling coffee powder fines. At step 51, themilled and blended coffee intermediate 30 is fed into the recycling linefrom the fines collector and is therefore incorporated into the productduring the spray-drying stage.

It has been found that the milled and blended coffee intermediate formedby jet milling has very good dispersion characteristics in liquids (suchas hot water or concentrated liquid coffee extract).

EXAMPLES

To illustrate the beneficial dispersion qualities of the jet milled andblended coffee intermediate, the following samples were prepared asfollows:

Sample 1 (Comparative)

100% Arabica beans, roasted to colour 8.5 La, then cryogenically groundusing prior art techniques. 15% by dry weight of the resultant groundmaterial was then dry mixed by hand with 85% of Arabica-based driedsoluble coffee—end composition 15% by dry weight roasted ground coffee,85% by dry weight equivalent soluble coffee.

Sample 2

15% Arabica beans roasted to colour 8.5 La, then jet milled with 85%Arabica-based, dried soluble coffee—end composition 15% by dry weightroasted ground coffee, 85% by dry weight equivalent soluble coffee.

Sample 3

30% Arabica beans roasted to colour 8.5 La, then jet milled with 70%Arabica-based, dried soluble coffee to form blended intermediate. 50% bydry weight of blended intermediate dry mixed by hand with 50% by dryweight of Arabica-based dried soluble coffee—end composition 15% by dryweight roasted ground coffee, 85% by dry weight equivalent solublecoffee.

Sample 4

50% Arabica beans roasted to colour 8.5 La, then jet milled with 50%Arabica-based, dried soluble coffee to form blended intermediate. 30% bydry weight of blended intermediate dry mixed by hand with 70% by dryweight of Arabica-based dried soluble coffee—end composition 15% by dryweight roasted ground coffee, 85% by dry weight equivalent solublecoffee.

Beverages were then prepared from the samples and dry and wet Helos(with and without ultrasound) particle size distributions were measured,with the following results:

% roasted ground coffee:% Wet Helos - Wet Helos - soluble Dry HelosStirred D90 Ultrasound Sample coffee D90 μm μm D90 μm 1 15:85 27.2 69.422.1 2 15:85 10.5 28.5 17.8 3 15:85 17.4 35.6 23.1 4 15:85 27.2 60.729.8

Wet Helos of the stirred sample represents the particle size when firstmade up and is higher where there is poor dispersion of the finelyground roasted coffee particles in water, thereby forming “clumps” ofmaterial.

That clumps are formed can be determined by comparing to the Wet Heloswith ultrasound measurement. The ultrasound acts to break up the clumps(if present).

As can be seen from the results, the comparative Sample 1 formed withcryogenically-ground roasted coffee had poor dispersion characteristicsand significant clumping—verified by the large difference between thewet Helos figures with and without ultrasound—even though the producthad the same total roasted ground coffee content as Samples 2 to 4. Bycomparison, Samples 2 and 3 of the present disclosure have much betterdispersion where the milled and blended coffee intermediate has 15 or30% by dry weight roasted ground coffee. Sample 4 with 50% by dry weightroasted ground coffee shows some improvement over the prior artcomposition but less than Samples 2 and 3.

Another aspect of the present disclosure relates to a novel freeze-driedsoluble coffee product having an appearance reminiscent of roastedground coffee.

It has been surprisingly discovered that the addition of roasted groundcoffee of small particle size to a freeze-dried soluble coffee productcan produce a darkening of the end product that results in thefreeze-dried product looking more similar to roasted ground coffee thanprior art freeze-dried coffee products.

The roasted ground coffee particles are preferably colloidal in sizewith a dry Helos particle size distribution D90 of less than or equal to100 microns, preferably less than or equal to 50 microns, morepreferably less than or equal to 30 microns.

The roasted ground coffee may constitute 5 to 30% by dry weight of thefreeze-dried product.

The roasted ground coffee may be derived from cryogenic milling of wholeroasted coffee beans. However, preferably, the roasted ground coffee isobtained by the milling process of the present disclosure describedabove with reference to

FIG. 1 in which the roasted ground coffee is a component of the milledand blended coffee intermediate.

The roasted ground coffee may be incorporated into the product by highshear mixing. Preferably, where the milled and blended coffeeintermediate of the present disclosure is to be used, the roasted groundcoffee is incorporated using one of the processes described above withreference to FIGS. 4 and 5.

The freeze-dried coffee end product has a colour of 13 to 30 La units onthe Lange scale, preferably 16 to 25 La units, more preferably 17 to 20La units.

The density of the soluble coffee product also has an affect on thecolour. Typically the denser the product the darker the colour. However,it is undesirable to have a soluble product that is too dense. Hence thepresent disclosure provides a flexible alternative which can be usedseparately from (or in combination with) control of the density of theproduct to select the desired product colour.

FIG. 8 illustrates results for a first set of three sample products, Ato C. For all three samples A to C the total solids (soluble coffeesolids and roasted ground coffee solids where applicable) concentrationof the product fed to the freeze-drier was 50% and the drying time was3.37 hours. Samples A to C had the following characteristics:

Sample A (Comparative Example)

Standard Net Robusta concentrated extract was foamed and freeze-driedusing known prior art techniques without the inclusion of any roastedground coffee. The datum colour change of 0 is set for a density ofSample A of 210 g/l. An increased density of 220 g/l results in a colourchange of −1.5 La units. An increased density of 230 g/l results in acolour change of −2.7 La units.

Sample B

A freeze-dried product according to the process of FIG. 5 a with roastedground coffee added after foaming with the end product comprising 15% bydry weight roasted ground coffee and 85% by dry weight equivalentsoluble coffee.

Compared to Sample A, Sample B produced a darker product with a colourchange of −3.0 La units at a density of 210 g/l; −3.8 La units at adensity of 220 g/l.

Sample C

A freeze-dried product according to the process of FIG. 4 a with roastedground coffee added before foaming with the end product comprising 15%by dry weight roasted ground coffee and 85% by dry weight equivalentsoluble coffee.

Compared to Sample A, Sample C produced a darker product with a colourchange of −1.5 La units at a density of 210 g/l; −2.4 La units at adensity of 220 g/l and −3.4 La units at a density of 230 g/l.

The results may be tabulated as follows:

Color change from datum Sample Density (g/l) (La) A 210 0 A 220 −1.5 A230 −2.7 B 210 −3.0 B 220 −3.8 C 210 −1.5 C 220 −2.4 C 230 −3.4

The following table illustrate results for a second set of two samplegroups of products D and E subjected to differing solids concentrationsand drying times. Sample groups D and E had the followingcharacteristics:

Sample D (Comparative Example)

Standard Net Arabica concentrated extract was foamed and freeze-driedwithout the inclusion of any roasted ground coffee. The datum colourchange of 0 was set for a density of sample of 220 g/l for threeconditions; feed to dryer solids concentration of 56% with 3 hrs dryingtime, feed to dryer solids concentration of 60% with 3 hrs drying timeand feed to dryer solids concentration of 56% with 3.37 hrs drying time.

Sample E

A freeze-dried product according to the process of FIG. 4 a with roastedground coffee added before foaming with the end product comprising 15%by dry weight roasted ground coffee and 85% by dry weight equivalentsoluble coffee and a density of 220 g/l. The same three conditions asSample D were evaluated.

Total solids concentration Color change from Sample fed to dryer (%)Drying time (Hrs) datum (La) D 56 3.0 0 E 56 3.0 −11.05 D 60 3.0 0 E 603.0 −7.45 D 56 3.37 0 E 56 3.37 −9.35

As can be seen from the data above, the inclusion of the roasted groundcoffee produces a marked darkening of the end product compared to a puresoluble coffee product.

It has also been found that the freeze-dried product is more reminiscentof roasted ground coffee where it is ground at step 23 to a particlesize of 0.3 to 3.5 mm, preferably 0.3 to 2.5 mm, more preferably 0.3 to1.5 mm.

The milled and blended coffee product described above or the solublecoffee product described above or the freeze-dried soluble coffeeproduct described above may be packaged for sale in a container such asa jar 101 as shown in FIG. 9. Alternatively, the milled and blendedcoffee product or the soluble coffee product or the freeze-dried solublecoffee product may be packaged in a container suitable for use in abeverage preparation machine. For example, FIG. 10 shows a suitablecontainer in the form of a cartridge 102 that may be used in a beveragepreparation machine 103 as shown in FIG. 11.

The product may contain one or more additional beverage components suchas natural or artificial sweeteners, dairy or non-dairy based creamers,lactose, vegetable fat, whey proteins, emulsifiers, stabilisers,modified starches, carriers, fillers, flavours, colours, nutrients,preservatives, flow agents or foaming agents.

1. A coffee milling process comprising the steps of: a) introducingparticles of a roasted coffee precursor into a milling chamber; b)introducing particles of soluble coffee into the milling chamber; c)jetting a gas into the milling chamber to mobilize the particles of theroasted coffee precursor and the particles of the soluble coffee; and d)producing a milled and blended coffee product by comminuting theparticles of the roasted coffee precursor by self-collision of theparticles of the roasted coffee precursor and by collision of theparticles of soluble coffee with the particles of the roasted coffeeprecursor within the milling chamber.
 2. The coffee milling process asclaimed in claim 1 wherein the particles of the roasted coffee precursorand the particles of the soluble coffee are mixed together beforeintroduction into the milling chamber.
 3. The coffee milling process asclaimed in claim 1 wherein the particles of the roasted coffee precursorand the particles of the soluble coffee are introduced separately intothe milling chamber.
 4. The coffee milling process as claimed in claim 1wherein the particles of the roasted coffee precursor in step a) are ata temperature of between 5 and 30 degrees Celsius.
 5. The coffee millingprocess as claimed in claim 1 wherein the milling chamber is not subjectto cryogenic cooling during the steps b), c) and d).
 6. The coffeemilling process as claimed in claim 1 wherein the milled and blendedcoffee product produced in step d) comprises 10 to 80% by dry weightroasted ground coffee and 20 to 90% by dry weight soluble coffee.
 7. Thecoffee milling process as claimed in claim 1 wherein the milled andblended coffee product produced in step d) comprises 10 to 70% by dryweight roasted ground coffee and 30 to 90% by dry weight soluble coffee.8. The coffee milling process as claimed in claim 7 wherein the milledand blended coffee product produced in step d) comprises 15 to 50% bydry weight roasted ground coffee and 50 to 85% by dry weight solublecoffee.
 9. The coffee milling process as claimed in claim 8 wherein themilled and blended coffee product produced in step d) comprises 50% bydry weight roasted ground coffee and 50% by dry weight soluble coffee.10. The coffee milling process as claimed in claim 1 wherein in step d)the comminution results in the milled and blended coffee product havinga dry Helos particle size distribution D90 of less than or equal to 40microns.
 11. The coffee milling process as claimed in claim 10 whereinin step d) the comminution results in the milled and blended coffeeproduct having a dry Helos particle size distribution D90 of less thanor equal to 30 microns.
 12. The coffee milling process as claimed inclaim 1 wherein the particles of roasted coffee precursor are wholeroasted coffee beans.
 13. The coffee milling process as claimed in claim1 wherein the particles of roasted coffee precursor are coarsely-groundroasted coffee beans.
 14. The coffee milling process as claimed in claim1 wherein the particles of soluble coffee are particles of spray-driedinstant coffee, particles of freeze-dried instant coffee, or a mixturethereof.
 15. The coffee milling process as claimed in claim 1 whereinthe gas jetted into the milling chamber in step b) is nitrogen, air, ora mixture thereof.
 16. The coffee milling process as claimed in claim 15wherein the gas is at a temperature between −20 degrees Celsius andambient temperature.
 17. A milled and blended coffee product produced bythe process of claim
 1. 18. A process of forming a freeze-dried solublecoffee product, comprising the steps of: (i) forming a concentratedcoffee extract; (ii) foaming and pre-freezing the concentrated coffeeextract to form a foamed and pre-frozen coffee intermediate; (iii)freezing the foamed and pre-frozen coffee intermediate to form a frozencoffee intermediate; (iv) grinding and sieving the frozen coffeeintermediate to form a ground coffee intermediate; and (v) drying theground coffee intermediate to form the freeze-dried soluble coffeeproduct; wherein prior to step (ii) and/or step (iii) a milled andblended coffee intermediate is incorporated; and wherein the milled andblended coffee intermediate comprises 10 to 80% by dry weight roastedground coffee and 20 to 90% by dry weight soluble coffee.
 19. A processof forming a spray-dried soluble coffee product, comprising the stepsof: i) forming a concentrated coffee extract; ii) foaming theconcentrated coffee extract to form a foamed coffee intermediate; iii)optionally filtering and homogenizing the foamed coffee intermediate toform a filtered and homogenized coffee intermediate; and iv) spraydrying the foamed coffee intermediate or the filtered and homogenizedcoffee intermediate to form the spray-dried soluble coffee product;wherein prior to step ii) and/or step iv) a milled and blended coffeeintermediate is incorporated; and wherein the milled and blended coffeeintermediate comprises 10 to 80% by dry weight roasted ground coffee and20 to 90% by dry weight soluble coffee.
 20. The process of claim 18wherein the milled and blended coffee intermediate comprises 10 to 70%by dry weight roasted ground coffee and 30 to 90% by dry weight solublecoffee.
 21. The process of 19 wherein the milled and blended coffeeintermediate comprises 15 to 50% by dry weight roasted ground coffee and50 to 85% by dry weight soluble coffee.
 22. The process of claim 21wherein the milled and blended coffee intermediate comprises 50% by dryweight roasted ground coffee and 50% by dry weight soluble coffee . 23.The process of claim 22 wherein the milled and blended coffeeintermediate has a dry Helos particle size distribution D90 of less thanor equal to 40 microns.
 24. The process of claim 23 wherein the milledand blended coffee intermediate has a dry Helos particle sizedistribution D90 of less than or equal to 30 microns.
 25. The process ofclaim 18 wherein the freeze-dried or spray-dried coffee productcomprises 5 to 30% by dry weight roasted ground coffee and 70 to 95% bydry weight equivalent soluble coffee.
 26. The process of claim 25wherein the freeze-dried or spray-dried coffee product comprises 10 to20% by dry weight roasted ground coffee and 80 to 90% by dry weightequivalent soluble coffee.
 27. The process of claim 26 wherein thefreeze-dried or spray-dried coffee product comprises 15% by dry weightroasted ground coffee and 85% by dry weight soluble coffee.
 28. Theprocess of claim 18 wherein the soluble coffee of the milled and blendedcoffee intermediate comprises spray-dried instant coffee, freeze-driedinstant coffee, or a mixture thereof.
 29. The process of claim 28wherein the ground coffee intermediate prior to drying has a totalcoffee solids concentration of greater than or equal to 52% and lessthan or equal to 63%.
 30. The process of claim 20 wherein the coffeeintermediate prior to drying has a total coffee solids concentration ofgreater than or equal to 52% and less than or equal to 63%.
 31. Theprocess of claim 30 wherein the total coffee solids concentration is 56%to 60%.
 32. A soluble coffee product produced by the process of claim18.
 33. A freeze-dried soluble coffee product comprising 5 to 30% by dryweight roasted ground coffee and 70 to 95% by dry weight equivalentsoluble coffee, wherein the roasted ground coffee has a dry Helosparticle size distribution D90 of less than or equal to 100 microns; andthe freeze-dried soluble coffee product has a color of 13 to 30 La unitson the Lange scale.
 34. The freeze-dried soluble coffee product asclaimed in claim 33, the coffee product comprising 10 to 20% by dryweight roasted ground coffee and 80 to 90% by dry weight equivalentsoluble coffee.
 35. The freeze-dried soluble coffee product as claimedin claim 34, the coffee product comprising 15% by dry weight roastedground coffee and 85% by dry weight equivalent soluble coffee.
 36. Thefreeze-dried soluble coffee product as claimed in claim 35 wherein theroasted ground coffee has a dry Helos particle size distribution D90 ofless than or equal to 50 microns.
 37. The freeze-dried soluble coffeeproduct as claimed in claim 36 wherein the roasted ground coffee has adry Helos particle size distribution D90 of less than or equal to 30microns.
 38. The freeze-dried soluble coffee product as claimed in claim37 wherein the freeze-dried soluble coffee product has a color of 16 to25 La units on the Lange scale.
 39. The freeze-dried soluble coffeeproduct as claimed in claim 38 wherein the freeze-dried soluble coffeeproduct has a color of 17 to 20 La units on the Lange scale.
 40. Thefreeze-dried soluble coffee product as claimed in claim 39 wherein thefreeze-dried soluble coffee product has a density of 185 to 265 g/liter.41. The freeze-dried soluble coffee product as claimed in claim 40wherein the freeze-dried soluble coffee product has a density of 205 to235 g/liter.
 42. The freeze-dried soluble coffee product as claimed inclaim 41 wherein the freeze-dried soluble coffee product has a densityof 225 g/liter.
 43. The freeze-dried soluble coffee product as claimedin claim 42 wherein the freeze-dried soluble coffee product has aparticle size range of 0.3 to 3.5 mm.
 44. The freeze-dried solublecoffee product as claimed in claim 43 wherein the freeze-dried solublecoffee product has a particle size range of 0.3 to 2.5 mm.
 45. Thefreeze-dried soluble coffee product as claimed in claim 44 wherein thefreeze-dried soluble coffee product has a particle size range of 0.3 to1.5 mm.
 46. A container containing the milled and blended coffee productof claim
 17. 47. A container containing the soluble coffee product ofclaim 32 wherein the container is one of the group consisting of abottle, a jar, a tin, a refill pack, a sachet, a stick pack, a filterbag, a container suitable for use in a beverage preparation machinecomprising a flexible pad formed at least partly from filteringmaterial, and a container for a beverage preparation machine comprisinga rigid, semi-rigid or flexible cartridge formed from substantially air-and water-impermeable materials.
 48. The container of claim 46 furthercontaining one or more additional beverage components selected from thegroup consisting of natural sweeteners, artificial sweeteners, dairybased creamers, non-dairy based creamers, lactose, vegetable fat, wheyproteins, emulsifiers, stabilizers, modified starches, carriers,fillers, flavors, colors, nutrients, preservatives, flow agents andfoaming agents.
 49. A beverage preparation machine in combination withat least one container suitable for use in the beverage preparationmachine selected from the group consisting of a flexible pad formed atleast partly from filtering material, rigid cartridge, semi-rigidcartridge and flexible cartridge formed from substantially air- andwater-impermeable materials, the at least one container containing themilled and blended coffee product of claim
 17. 50. (canceled) 51.(canceled)
 52. A beverage preparation machine in combination with atleast one container suitable for use in the beverage preparation machineselected from the group consisting of a flexible pad formed at leastpartly from filtering material, rigid cartridge, semi-rigid cartridgeand flexible cartridge formed from substantially air- andwater-impermeable materials, the at least one container containing thesoluble coffee product of claim
 32. 53. A beverage preparation machinein combination with at least one container suitable for use in thebeverage preparation machine selected from the group consisting of aflexible pad formed at least partly from filtering material, rigidcartridge, semi-rigid cartridge and flexible cartridge formed fromsubstantially air- and water-impermeable materials, the at least onecontainer containing freeze-dried soluble coffee product of claim 33.